Disodium tetracarbonylferrate

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Disodium tetracarbonylferrate
Image:Disodium tetracarbonylferrate.jpg
General
Systematic name disodium tetracarbonylferrate
Other names disodium iron tetracarbonyl
Collman's reagent
Molecular formula C4FeNa2O4
Molar mass 213.87 g/mol
Appearance colourless solid
CAS number [14878-31-0]
Properties
Density and phase 2.16 g/cm3, solid
Solubility in water decomposed
Other solvents THF, DMF,dioxane
Melting point 270-273 °C (K+ salt)
Structure
Coordination
geometry
tetrahedral
Crystal structure distorted tetrahedron
Dipole moment 0 D
Hazards
MSDS External MSDS
Main hazards pyrophoric
NFPA 704
R/S statement R:
S:
RTECS number
Supplementary data page
Structure and
properties
n, εr, etc.
Thermodynamic
data
Phase behaviour
Solid, liquid
Spectral data UV, IR, NMR, MS
Related compounds
Related compounds K2Fe(CO)4
Na2Fe2CO8
Fe(CO)5
Except where noted otherwise, data are given for
materials in their standard state (at 25 °C, 100 kPa)
Infobox disclaimer and references

Disodium tetracarbonylferrate is the chemical compound with the formula Na2[Fe(CO)4]. This oxygen-sensitive colourless solid is employed in organic synthesis",[1] mainly to synthesise aldehydes.[2] It is commonly used with dioxane complexed to the sodium cation, this dioxane solvate being known as Collman's Reagent.[3] The tetracarbonylferrate dianion is tetrahedral.[4]

Contents

[edit] Synthesis

The reagent was reported by Cooke in 1970.[5] The current synthesis entails the reduction of a solution of iron pentacarbonyl in tetrahydrofuran by sodium-naphthenide. The efficiency of the synthesis depends on the quality of the iron pentacarbonyl.[1]

Fe(CO)5 + 2 Na → Na2[Fe(CO)4] + CO

[edit] Reactions

The reagent was originally described for the conversion of primary alkyl bromides, RBr, to the corresponding aldehydes in a two-step, "one-pot" reaction:[5]

Na2[Fe(CO)4] + RBr → Na[RFe(CO)4] + NaBr

This solution is then treated sequentially with PPh3 and then acetic acid to give the aldehyde, RCHO.

Disodium tetracarbonylferrate can be used to convert acid chlorides to aldehydes. As for Cooke’s early discovery, an iron acyl complex undergoes protonolysis to give the aldehyde.

Na2[Fe(CO)4] + RCOCl → Na[RC(O)Fe(CO)4] + NaCl
Na[RC(O)Fe(CO)4] + HCl → RCHO + "Fe(CO)4" + NaCl

Disodium tetracarbonylferrate reacts with alkyl halides (RX) to produce alkyl complexes:

Na2[Fe(CO)4] + RX → Na[RFe(CO)4] + NaX

Such iron alkyls can be converted to the corresponding carboxylic acid and acid halides:

Na[RFe(CO)4] + O2, H+ →→ RCO2H + Fe...
Na[RFe(CO)4] + X2 → RC(O)X + FeX2 + 3 CO + NaCl

One attraction of these methods is the low cost of the iron carbonyl as well as the fact that the procedures are relatively “green” because the side product is iron-based.

[edit] References

  1. ^ a b Strong, H.; Krusic, P. J.; San Filippo, J. "Sodium Carbonyl Ferrate, Na2Fe(CO)], Na2[Fe2(CO)8], and Na2[Fe3(CO)11]. Bis[μ-Nitrido-Bis(triphenylphosphorus)(1+] Undecarcarbonyltriferrate(2-), [(Ph3P)2N]2[Fe3(CO)11]" Inorganic Syntheses, 1990, volume 28, 203-207. ISBN 0-471-52619-3
  2. ^ Pike, Robert D., (2001). Disodium Tetracarbonylferrate (II-). Encyclopedia of Reagents for Organic Synthesis.
  3. ^ Miessler, G. L., Tarr, D. A. (2004). Inorganic chemistry. Upper Saddle River,New Jersey: Pearson Publication.
  4. ^ H. B. Chin, R. Bau (1976). "The Crystal Structure of Disodium Tetracarbonylferrate. Distortion of the Tetracarbonylferrate(2-) Anion in the Solid State". Journal of the American Chemical Society 98: 2434 - 2439. DOI:10.1021/ja00425a009. 
  5. ^ a b Cooke, M. P., Jr., "Facile Conversion of Alkyl Bromides into Aldehydes Using Sodium Tetracarbonylferrate(-II)", Journal of the American Chemical Society, 1970, volume 92, pages 6080-2. JACSAT ISSN: 0002-7863.

[edit] Further reading

  • J. P. Collman (1975). "Disodium Tetracarbonylferrate, a Transition Metal Analog of a Grignard reagent". Accounts of Chemical Research 8: 342 - 347. DOI:10.1021/ar50094a004. 
  • C. Ungurenasu, C. Cotzur (1982). "Disodium Tetracarbonylferrate: A Reagent for Acid Functionalization of Halogenated Polymers". Journal Polymer Bulletin 6: 299-303. DOI:10.1007/BF00255401. 
  • V. W. Hieber, G. Braun (1959). "". Zeitschrift für Naturforschung 146: 132. 

[edit] External Links